Iron‐Catalyzed Functionalization of 3‐Benzylideneindoline Through Tandem Csp²–Csp³ Bond Formation/Isomerization with π‐Activated Alcohols

Abstract

A new synthetic protocol was developed for the selective synthesis of diverse 3‐substituted indoles through tandem carbon–carbon bond formation and isomerization of 3‐benzylidene‐1‐tosylindoline by direct use of alcohols as alkylating agents in the presence of catalytic FeCl3. This method is applicable to a wide range of substrates containing varieties of functional groups. Direct use of alcohols, such as benzylic, allylic, and propargylic alcohols, as electrophiles and the use of non‐toxic iron catalyst makes this strategy attractive and environmentally benign. A plausible mechanism has also been proposed for this tandem reaction.